Examen des paramètres de l'Hamiltonien de spin de Mn2+ substitué a M, dans les fluoperovskites AMF3, dans la phase tétragonale de RbCaF3 et dans les composés A2MF4

Rousseau, Jean‐Jacques; Leblé, A.; Fayet, J. C.

doi:10.1051/jphys:0197800390110121500

Cited by 55 publications

(14 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the same vein as for octahedral NiF 6 4– , MnF 6 4– , or FeF 6 3– units in cubic fluoroperovskites, ,− both A s and q s quantities, corresponding to the e g (σ) orbital, are strongly dependent upon the metal–ligand distance, while A p is much less sensitive.…”

Section: Resultsmentioning

confidence: 79%

Key Role of Deep Orbitals in the d_x²–y²–d_3z²–r² Gap in Tetragonal Complexes and 10Dq

Aramburu

Moreno

2021

J. Phys. Chem. A

View full text Add to dashboard Cite

Using first-principles calculations, we show that the origin of the intrinsic a 1g (∼3z 2 − r 2 )−b 1g (∼x 2 − y 2 ) splitting, Δ int , in tetragonal transition-metal complexes and the variations of the cubic field splitting, 10Dq, with the metal−ligand distance, R, are much more subtle than commonly thought. As a main novelty, the key role played by covalent bonding with deep valence ligand levels and thus the inadequacy of too simple models often used for the present goal is stressed. Taking as a guide the isolated D 4h CuF 6 4− complex, it is proved that Δ int essentially arises from bonding with deep 2s(F) orbitals despite them lying ∼23 eV below 2p(F) orbitals. This conclusion, although surprising, is also supported by results on octahedral fluoride complexes where the contribution to 10Dq splitting from bonding with 2s(F) orbitals is behind its strong R dependence, stressing that explanations based on the crystal-field approach are simply meaningless.

show abstract

Section: Resultsmentioning

confidence: 79%

Key Role of Deep Orbitals in the d_x²–y²–d_3z²–r² Gap in Tetragonal Complexes and 10Dq

Aramburu

Moreno

2021

J. Phys. Chem. A

View full text Add to dashboard Cite

show abstract

“…In the case of substitutional Mn2' impurities in the fluoride lattices with cubic or nearly cubic local symmetries it has been shown that A, is rather sensitive to the host lattice [12]. The origin of the sensitivity has been explained through the strong dependence of A, upon the equilibrium impurity-ligand distance R [13].…”

Section: Comments On the Isotropic Superhyperfine Constant A For Fe3mentioning

confidence: 97%

ESR Investigation of Phase Transitions in Some Elpasolite‐Type Fluorides

Dance¹,

Grannec²,

Tressaud³

et al. 1992

Physica Status Solidi (b)

View full text Add to dashboard Cite

Structural phase transition temperatures are determined for some elpasolite‐type fluorides Rb2KMF6 (M = Ga, Cr, Fe) through electron spin resonance. The results are compared with low temperature X‐ray diffraction and calorimetric results. For the new elpasolite Rb2KGaF6 a transition temperature of T ≈ 120 K is detected using Cr3+ and Fe3+ as paramagnetic probes. In the case of Rb2KGaF6:Fe3+ the isotropic superhyperfine constant As is well resolved in the powder spectrum. An analysis of experimental As values found for Fe3+ in different fluoride lattices is reported. In the case of paramagnetic elpasolites, the variation of the linewidth of the ESR spectra of Rb2KCrF6 and Rb2KFeF6 with temperature confirms the occurrence of a phase transition at T(Cr) ≈ 150 K and T(Fe) ≈ 170 K. The Cr3+ or Fe3+ doped K2NaGaF6 elpasolite which remains cubic down to very low temperatures is also checked. As expected no change in the ESR spectra occurs in this case.

show abstract

“…Mn 2+ -doped cubic fluoroperovskites are model systems whose equilibrium impurityligand distance, R 0 , has been explored by different methods [5][6][7]12]. However, there are several important questions which need to be clarified:…”

Section: Introductionmentioning

confidence: 99%

“…The present work is aimed at exploring the local structure and optical and vibrational properties associated with Mn 2+ impurities in cubic AMF 3 fluoroperovskites [4][5][6][7][8][9][10][11][12][13][14] by means of a recent method for improving the embedding in the realm of the density functional theory (DFT) [15][16][17]. In this method the electronic density of a finite cluster is divided into two regions.…”

Section: Introductionmentioning

confidence: 99%

Optical and vibrational properties of MnF₆⁴⁻complexes in cubic fluoroperovskites: insight through embedding calculations using Kohn–Sham equations with constrained electron density

Garcı́a-Lastra

Wesołowski

Barriuso

et al. 2006

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

The local structure and optical and vibrational properties associated with Mn 2+ -doped cubic AMF 3 (A = K, Rb; M = Mg, Zn, Cd) fluoroperovskites are studied by means of embedding calculations using Kohn-Sham equations with constrained electron density. It is shown that while an electronic parameter like 10Dq essentially depends on the Mn 2+ -F − distance, the local vibration frequencies ω i (i = a 1g , e g modes) are dominated by the interaction between F − ligands and nearest M 2+ ions lying along bonding directions. The high ω a values observed for KMgF 3 :Mn 2+ and KZnF 3 :Mn 2+ , the huge variations of ω e and ω a frequencies when the host lattice is changed, as well as the increase of Huang-Rhys factors and the Stokes shift following the host lattice parameter, are shown to be related to this elastic coupling of the MnF 4− 6 complex to the rest of the host lattice. The present results support the conclusion that the Stokes shift is determined by the interaction of the excited 4 T 1g state with a 1g and e g local modes while the coupling with the t 2g shear mode is not relevant. The variations of local vibrational frequencies and the Stokes shift induced by a hydrostatic pressure on a given system are shown to be rather different to those produced by the chemical pressure associated with distinct host lattices.

show abstract

Examen des paramètres de l'Hamiltonien de spin de Mn2+ substitué a M, dans les fluoperovskites AMF3, dans la phase tétragonale de RbCaF3 et dans les composés A2MF4

Cited by 55 publications

References 26 publications

Key Role of Deep Orbitals in the d_x²–y²–d_3z²–r² Gap in Tetragonal Complexes and 10Dq

Key Role of Deep Orbitals in the d_x²–y²–d_3z²–r² Gap in Tetragonal Complexes and 10Dq

ESR Investigation of Phase Transitions in Some Elpasolite‐Type Fluorides

Optical and vibrational properties of MnF₆⁴⁻complexes in cubic fluoroperovskites: insight through embedding calculations using Kohn–Sham equations with constrained electron density

Contact Info

Product

Resources

About

Examen des paramètres de l'Hamiltonien de spin de Mn2+ substitué a M, dans les fluoperovskites AMF3, dans la phase tétragonale de RbCaF3 et dans les composés A2MF4

Cited by 55 publications

References 26 publications

Key Role of Deep Orbitals in the dx2–y2–d3z2–r2 Gap in Tetragonal Complexes and 10Dq

Key Role of Deep Orbitals in the dx2–y2–d3z2–r2 Gap in Tetragonal Complexes and 10Dq

ESR Investigation of Phase Transitions in Some Elpasolite‐Type Fluorides

Optical and vibrational properties of MnF64−complexes in cubic fluoroperovskites: insight through embedding calculations using Kohn–Sham equations with constrained electron density

Contact Info

Product

Resources

About

Key Role of Deep Orbitals in the d_x²–y²–d_3z²–r² Gap in Tetragonal Complexes and 10Dq

Key Role of Deep Orbitals in the d_x²–y²–d_3z²–r² Gap in Tetragonal Complexes and 10Dq

Optical and vibrational properties of MnF₆⁴⁻complexes in cubic fluoroperovskites: insight through embedding calculations using Kohn–Sham equations with constrained electron density